How to Build a Turf Roof

Confirm the building structure is sturdy enough to support the weight of the building materials, soil and plants necessary for a turf roof. For example, North Carolina building codes require the building have the structural strength to support a 100-pound-per-square-foot load for a roof garden.

Place rafters or girders across the roof space. Support the girders with beams. The girders should be spaced no more than 16 inches apart with beams every 5 feet. Use 2-by-8-inch girders or heavier for the roof supports.

Cover the roof girders with plywood. Use 3/4-inch exterior grade plywood nailed in place with 6d nails.

Cover the plywood with waterproof membrane. This protects the building from moisture infiltration into the building.

Add soil to the roof of the building. An extensive green roof commonly has between 1 and 6 inches of soil while intensive green roofs may have a soil depth of up to 24 inches. Low growing native plants are grown on extensive green turf roofs while a wider variety of plants thrive in an intensive garden.

Add an irrigation system to the roof. Drip irrigation works best because it reduces the amount of water necessary.

Plant the selected vegetation on the roof. Select plants that are native or hardy to the area. Add any landscape or decorative features to the turf roof.